Anchor bolt

ABSTRACT

An anchor bolt including a cylindrical body having a reduced diameter portion near one end and an outwardly flaring portion extending from the reduced diameter portion toward that one end. A pair of expansion members encircle the reduced diameter portion. Each expansion member is a curved resilient element extending through an angle greater than 180*, e.g. 220*, and the expansion members have cooperable interlock means for transmitting axial movement of one expansion member to the other. The two expansion members may be identical to each other, and each may have an outwardly projecting protuberance. One or both of the reduced diameter and outwardly flaring portions of the body may have a non-circular, e.g., elliptical, cross-sectional shape.

United States Patent 1 [11.1 3,766,819 Giannuzzi Oct. 23, 1973 [54]ANCHOR BOLT 259,211 4/1967 Austria 85/88 [75] Inventor: Louis N.Giannuzzi, Riverside,

C Primary Examiner-Edward C. Allen Att0meyAlan H. Levine [73] Ass1gnee:Die Cast and Forge Company, Inc.,

New Rochelle, NY. [22] Filed: Dec. 3, 1971 [57] ABSTRACT An anchor boltincluding a cylindrical body having a reduced diameter portion near oneend and an outwardly flaring portion extending from the reduced di- [52]U.S. Cl. 85/77, 85/88 ameter portion toward that one end. A pair ofexpan- [51] Int. Cl Fl6b 13/06 sion members encircle the reduceddiameter portion. [58] Field of Search 85/77, 78, 79, 86, Each expansionmember is a curved resilient element 85/87, 88, 51 extending through anangle greater than 180, e.g. a 220, and the expansion members havecooperable in- [56] References Cited terlock means for transmittingaxial movement of one UNITED STATES PATENTS expansion member to theother. The two expansion 3 277 770 10/1966 Mccuuoch 85/77 members may beidentical to each other, and each 3657955 4/1972 Mcxaymmxm 85/51 mayhave an outwardly projecting protuberance. One 8/1908 Capuw 85/77 orboth of the reduced diameter andoutwardly flaring 1,495,497 5/1924 Ogden85/88 po of the y y have a non-circular, -g-,

FOREIGN PATENTS OR APPLICATIONS cmss'sectmal shape 564,601 10/1958Canada 85/88 9 Claims, 8 Drawing Figures A3) fl) ANCHOR BOLT Thisinvention relates to anchor bolts of the type used to fasten articles tosurfaces of masonry or like material. In particular, the inventionrelates to the type of anchor bolt carrying an expansion means near oneof its ends.

When such an anchor is inserted into a bore drilled in a wall or othersurface, its expansion means is in a contracted condition because it islocated around the smallest diameter portion of the bolt body. Theexpansion means frictionally engages the wall of the bore so that as thebolt body is slowly withdrawn from the bore during the fasteningoperation, the body moves axially with respect to the expansion means.The axial movement brings a body portion of increased diameter into theexpansion means, thereby expanding the latter and causing it to tightlyengage the bore wall. As a result, the body is firmly anchored to thewall.

Anchor bolts of this type embodying various designs have been availablefor some time. However, each presents a problem from the point of viewof manufacture, shipping, and/or use.

It is an object of the present invention to provide an anchor bolt ofthe type described above which is simple and inexpensive to manufactureand assemble, which will remain assembled during shipmemnt, and which iseasy to use and reliable in performing its anchoring function.

It is a more specific object of the invention to provide an anchor bolthaving two separate expansion members which can be readily assembledwith the bolt body by hand, but which will nevertheless not becomedisassembled during shipment and use.

It is another object of the invention to provide such an anchor bolt inwhich the two independent expansion members are interlocked onceassembled with the bolt body to insure that both expansion membersparticipate in securing the body within a bore.

Additional objects and features of the invention will be apparent fromthe following description in which reference is made to the accompanyingdrawings.

In the drawings:

FIG. 1 is an elevational view of a bolt body forming part of an anchorbolt according to the present invention;

FIGS. 2 and 3 are cross-sectional views taken along lines 2-2 and 3--3,respectively, of FIG. 1;

FIG. 4 is an exploded perspective view of expansion members forming partof an anchor bolt according to the present invention;

FIG. 5 is an end elevational view of one of the expansion members;

FIG. 6 is an elevational view of an anchor bolt.according to thepresent'invention prior to use;

FIG. 7 is a cross-sectional view showing the anchor bolt within a borein a concrete wall prior to expansion of the expansion members, the boltbody being shown in elevation; and

FIG. 8 is a view similar to FIG. 7 showing the expansion members inexpanded condition as well as in elevation.

The anchor bolt chosen to illustrate the present invention comprises abolt body 10 and two expansion members 11 and 12. Body 10 has agenerally cylindrical shape, and is provided at one end with a screwthread 13. Although a screw thread is illustrated, this end of the boltbody could beprovided with a hook shape, or any other configuration bymeans of which an axial force can be exerted on the body to withdraw itfrom a bore into which it is placed.

Near its end 14, i.e., the end which is first inserted into a bore inwhich the anchor bolt is to be held, body 10 is formed with a reduceddiameter region 15. Merging with reduced diameter portion 15 is aflaring portion 16 of the bolt body which tapers outwardly toward end14.

Body 10 may have circular cross-sectional shape throughout its length.However, according to the invention, it is preferred that one or both ofthe reduced diameter portion 15 and flaring portion 16 have anoncircular cross-sectional shape. Preferably, portions 15. and 16 areelliptically shaped in cross-section, as shown in FIGS. 2 and 3.However, under certain circumstances it may be sufficient to make onlyone of these portions of elliptical shape.

For convenience of manufacture and assembly, expansion members 11 and 12are identical to each other. Consequently, only one, namely, expansionmembers 12, will be described in detail, with reference to FIGS. 4 and5.

In the present example, expansion member 12 is formed of sheet metal bymeans of a stamping operation, and hence it has a certain. inherentresilience. However, any other material having the strength andresilience characteristics required of the expansion members may beemployed.

Expansion member 12 has an arcuate shape conforming closely to the shapeof reduced diameter portion 15 of body 10. The main portion of member12, i.e., the portion between longitudinal edges 19 and 20 extendsthrough an arc of no more than and preferably slightly less than thisangle. Extending peripherally from edge 19 is a finger 21. Formed inedge 20 is a peripheral notch 22 adapted to accommodate the finger 21 ofexpansion member 11. Notch 22 is spaced from both end edges 17 of theexpansion member. The portion 23 of expansion member 12 on the side ofnotch 22 opposite edge 20 is peripherally extended, and the portion 24on the side of finger 21 opposite edge 19 is cut back. Between the endedge 25 of finger 21 and end edge 26 of portion 23, members 12 extendsthrough an angle greater than 180", this angle preferably being about220. At its midportion, expansion member 12 is formed with an outwardlyprojecting protuberance 27.

To assemble expansion members 11 and 12 with bolt body 10, as shown inFIG. 6, the concave face of each expansion member is held adjacent toreduced diameter portion 15, and the expansion member is pressed towardportion 15. Due to the inherent resilience of the I expansion membermaterial, finger 21 and portion 23 first move away from each other andultimately snap over body portion 15. Since only the relatively narrowfinger 21 and portion 23 are stressed during this assembly operation,the assembly can readily be performed manually. However, the grippingaction of finger 21 and portion 23 upon reduced diameter portion 15 ofbody 10 is sufficient to maintain each expansion member assembled withthe bolt body. It should be noted that this assembled condition ismaintained without the use of any additional fastening means.

With the anchor bolt in assembled condition, finger 21 of each expansionmember extends into notch 22 of the other expansion member. Thus, thefingers and notches serve as an interlock between the two expansionmembers, the purpose of which will be mentioned below.

The manner in which the anchor bolt may be used a illustrated in FIGS. 7and 8. It is assumed that an article 30 is to be secured to a concretewall 31. A bore 32 having a diameter slightly larger than the diameterof bolt body 10 is first drilled in wall 31.

The assembled anchor bolt is inserted into bore 32 with a portion of itsthreaded end 13 projecting from the bore. Article 30 is placed over thethreaded end 13 and against the exposed surface of wall 31, and a nut 33is threaded'onto bolt end 13.

As nut 33 is rotated, bolt body 10 is gradually withdrawn from bore 32.However, the frictional engagement between ex-pansion members 11 and 12and the wall of bore 32 hinders with-drawal of the expansion members.This action is augmented by the presence of protuberances 27 whichengage the wall of bore 32 and effectively prevent withdrawal of theexpansion members.

As bolt body 10 moves axially toward the left in FIGS. 7 and 8, flaringportion 16 of the bolt body enters between expansion members 11 and 12,as shown in FIG. 8, thereby expanding them, i.e., moving them radiallyaway from each other. This action tightly presses expansion members 11and 12 against the wall of bore 32, and ultimately the expansion membersprevent any further withdrawal, i.e., leftward movement of body 10. Boltbody 10 is therebyfirmly anchored in wall 31, and article 30 is securelymounted on the wall.

It sometimes happens that when two expansion members are employed, as inthe present invention, one of them may grip the wall of bore 32 beforethe other end and thereby prevent the other from ever tightly grippingthe wall of the bore. As a result, the holding power of the anchor boltis greately reduced. This possibility is prevented by the interlockprovided between the expansion members of the present invention. It willbe seen that when one of the expansion members 11 or 12 grips the wallof bore 32, and hence begins to move axially with respect to bolt body10, finger 21 of the expansion member which has gripped the wall willengage portion 23 of the other expansion member and cause it also tomove with respect to body 10. Consequently, both expansion members willsimultaneously be acted upon by flaring portion 16 and pressed tightlyagainst the wall of bore 32.

It has been found with some conventional anchor bolts that as nut 33 isrotated, bolt body 10 rotates with the nut and hence the bolt body'neverbecomes anchored. The reason is that the portions and 16 of the boltbodyare rotating inside the stationary expansion member. By making oneor both of body portions 15 and 16 non-circular, as described above,this possibility is avoided.

The invention has been shown and described in'preferred form only, andby way of example, and many variations may be made in the inventionwhich will still be comprised within its spirit. It is understood,therefore, that the invention is not limited to any specific form orembodiment except insofar as such limitations are included in theappended claims.

What is claimed is:

1. An anchor bolt comprising:

a. a cylindrical body having a reduced diameter portion near one end,and an outwardly flaring portion extending from said reduced diameterportion toward said one end, and

b. a pair of expansion members mounted on said reduced diameter portion,said expansion members being separate and independent of each other,

I. each of said expansion members being a curved resilient elementhaving a portion which extends in a circumferential direction through anangle greater than l, whereby each of said members may be manuallysnapped over said reduced diameter portion and will remain thereonwithout the need for additional fastening means, and

II. each of said expansion members having interlock means cooperablewith interlock means on the other ex-pansion member for transmittingmovement of each of said expansion members, axially in both directionswith re-spect to said body, to the other of said expansion members, saidinterlock means permitting separation of said expansion members in aradial direction, and said interlock means including a finger extendingperipherally from one longitudinal edge of each expansion member andcomprising a part of said expansion member portion which extends formore than and a peripheral notch in the other longitudinal edge thereofspaced from both end edges of the expansion member and adapted toaccommodate a like finger of the other expansion member, thecorresponding side edges of each said finger and notch being paralleland each said finger and notch being about equal in width so that eachsaid finger fits snugly within its respective notch.

2. An anchor bolt as defined in claim 1 wherein said expansion membersare identical to each other.

3. An anchor bolt as defined in claim 1 including a protuberanceprojecting radially outwardly from each of said expansion members.

4. An anchor bolt as defined in claim 1 wherein each of said expansionmembers extends through an angle of approximately 220.

.5.- An anchor bolt as defined in claim 1 wherein said reduced diameterportion of said body has a noncircular cross-sectional shape.

6. An anchor boltas defined in claim 5 wherein said reduced diameterportion has an elliptical crosssectional shape.

7. .An anchor bolt as defined in claim 1 wherein said outwardly flaringportion of said body has a noncircular cross-sectional shape.

8. An anchor bolt as defined in claim 7 wherein said outwardly flaringportion has an elliptical crosssectional shape.

9. An anchor bolt as defined in claim 1 wherein said reduced diameterand outwardly flaring portions of said body both have ellipticalcross-sectional shapes.

1. An anchor bolt comprising: a. a cylindrical body having a reduceddiameter portion near one end, and an outwardly flaring portionextending from said reduced diameter portion toward said one end, and b.a pair of expansion members mounted on said reduced diameter portion,said expansion members being separate and independent of each other, I.each of said expansion members being a curved resilient element having aportion which extends in a circumferential direction through an anglegreater than 180*, whereby each of said members may be manually snappedover said reduced diameter portion and will remain thereon without theneed for additional fastening means, and II. each of said expansionmembers having interlock means cooperable with interlock means on theother expansion member for transmitting movement of each of saidexpansion members, axially in both directions with respect to said body,to thE other of said expansion members, said interlock means permittingseparation of said expansion members in a radial direction, and saidinterlock means including a finger extending peripherally from onelongitudinal edge of each expansion member and comprising a part of saidexpansion member portion which extends for more than 180*, and aperipheral notch in the other longitudinal edge thereof spaced from bothend edges of the expansion member and adapted to accommodate a likefinger of the other expansion member, the corresponding side edges ofeach said finger and notch being parallel and each said finger and notchbeing about equal in width so that each said finger fits snugly withinits respective notch.
 2. An anchor bolt as defined in claim 1 whereinsaid expansion members are identical to each other.
 3. An anchor bolt asdefined in claim 1 including a protuberance projecting radiallyoutwardly from each of said expansion members.
 4. An anchor bolt asdefined in claim 1 wherein each of said expansion members extendsthrough an angle of approximately 220*.
 5. An anchor bolt as defined inclaim 1 wherein said reduced diameter portion of said body has anon-circular cross-sectional shape.
 6. An anchor bolt as defined inclaim 5 wherein said reduced diameter portion has an ellipticalcross-sectional shape.
 7. An anchor bolt as defined in claim 1 whereinsaid outwardly flaring portion of said body has a non-circularcross-sectional shape.
 8. An anchor bolt as defined in claim 7 whereinsaid outwardly flaring portion has an elliptical cross-sectional shape.9. An anchor bolt as defined in claim 1 wherein said reduced diameterand outwardly flaring portions of said body both have ellipticalcross-sectional shapes.